ci: use Node.js 24 runtime for actions and bump release node to 22

Opt into Node.js 24 for GitHub Actions runners (actions/checkout@v4,
actions/setup-node@v4) to silence deprecation warnings. Also bump
release.yml from node 20 to 22 to match ci.yml.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -5,6 +5,9 @@ on:
     branches: [master, main]
   pull_request:
 
+env:
+  FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: true
+
 jobs:
   ci:
     name: Typecheck & Lint